Where to start... it looks too plain;
- the grass and stone look noobish and bad against the buildings, put barrens tile sets.
- how do you want the camera to move in such tight space, space everything out more(this way it won't look so.. brown and plain at first sight).. and raise and lower terrain too when it's spaced out more, too flat.
- add units, citizens.. guards..
- add landmarks in the vicinity, maybe a swamp nearby, town is next to a mountain, or river through town, be creative.
- add a night sky and torches
- if you will put rain, then add a few puddles here and there.
- add stables, and animals (farms).
- you need trees, animated grass maybe too.
- fog effect is a must.